The present invention relates to an improved coupling device which is utilized for tapping kegs of fluids which are kept under pressure. This improved coupling device is particularly applicable for tapping a keg of beer.
In operation, the coupler is inserted by depression and rotation into a valve assembly which is located at the opening of the container of fluid such as beer. Valve assemblies for this purpose have been in commercial use for many years. One such valve assembly is described in U.S. Pat. No. 4,181,143 issued to Fallon. The valve assembly comprises a ball valve which is forced against its seat by spring pressure. When a counteracting force pushes the ball valve off its seat, the fluid under pressure is permitted to escape through the opening between the ball valve and its seat.
The function of the coupler is to create an inlet for a pressurizing gas and an exit apparatus by which the fluid can be removed from the container and poured into a glass or cup. Two general types of couplers are presently in use; a commercial coupler which is designed to accomodate a source of counter pressure such as CO.sub.2 and a consumer coupler which generates its counter pressure through air which is compressed by means of a piston. The consumer coupler in this mode is commonly known as a picnic pump system.
In a conventional commercial coupler, such as that described in U.S. Pat. No. 4,181,143 issued to Fallon, the coupler is inserted by rotation into the valve assembly. The coupler contains cams at its lower face and they are accommodated by lugs which are on the inner circumference of the container opening adjacent the valve assembly. Then, by a separate action, a handle or cam actuates a movable probe inside the coupler which pushes against the ball valve assembly and thereby permits the flow of fluid into and out of the container through appropriate channels. The probe which forces the ball valve away from its seat moves relative to its surrounding cam which secures the coupler to the container. In order to achieve this, an expensive actuating system is necessary.
In the conventional picnic pump system, once again the coupler is inserted by rotation into the valve assembly. This consumer coupler also contains cams at its lower face and they are accommodated by lugs which are on the inner circumference of the container opening adjacent the valve assembly. After the consumer coupler is secured to the container, a second rotating action causes a movable probe to further rotate downward relative to the locked cams and push the ball valve off its seat to thereby permit the flow of fluid into and out of the container through appropriate channels. Once again, having the probe move relative to the cam is an expensive product to manufacture and if the probe is accidentally lowered before the cam is locked in place, the pressurized fluid will spew out of the canister. Having the probe move relative to its surrounding cams also subjects the apparatus to more leakage of fluid in this area. The pressure from this consumer coupler is generated by a piston at the top, which compresses air and forces it into the container when the piston is forced downward. The presently used consumer couplers are made in several pieces which are attached together by a tongue and groove assembly and other similar mechanisms. This multipiece construction adds cost to the product.
Therefore, the prior art has couplers wherein the valve opening probe moves relative to the cams which secure the coupler to the valve housing or container opening. The actuation of the probe requires a second rotational movement or lever action after the coupler has been secured to the container. This movable probe assembly has many disadvantages. First, it is expensive to produce. Second, if the movable probe is in its down position before the coupler is firmly secured to the container, the fluid under pressure inside the container may spew out. Third, it is possible for leaks to occur at the side of the gap between the movable probe and its surrounding support structure.
The couplers discussed in the prior art are also made of multiple piece construction. This further increases the cost of manufacture and assembly of the units.